1. Field of the Invention
The invention relates generally to a piston cylinder unit. In particular, the invention relates to a piston cylinder unit having a mechanical interlock.
2. Description of the Related Art
A mechanical interlock in gas springs, which comprises a first locking element on the piston-side end of the piston rod and a second locking element on the opposite end of a cylinder closed by a sealing and guide package is disclosed in DE 23 45 503 A1. In a first embodiment, the first locking element comprises a cone pointing toward the second locking element; adjacent to the cone is an annular groove. The second locking element is designed as a sleeve, which has a groove in its inside circumference. A spring ring is laid loosely in this groove. The sleeve is held axially in place by a pleat in the cylinder and by the sealing and guide mechanism. In a second embodiment, a cam drum is mounted on the piston side of the piston rod. This drum comprises several cams distributed around its outer circumference. The cams extend radially outward from the drum. A cam crown and a cam sleeve, provided on the sealing and guide package, are attached to the cylinder by a pleat in the cylinder. The cam sleeve and the cam crown comprise curved sections in the form of radially inward-projecting cams. The cams of the cam drum have repelling flanks, and the cam sleeve and the cam crown comprise both repelling flanks and catches.